Inclosed motor pump unit



Nov. 7, 1933.

J. A. GRIER 1,934,189

INCLOSED MOTOR PUMP UNIT Filed Aug. 12, 1929 a Sheets-Sheet 1 IN VEN TOR. Jam! A1. FRED 6/9/52.

' ATTORNEY Patented Nov. 7, 1933 UNITED STATES PATENT OFFICE INCLOSED MOTOR PUMP UNIT Application August 12, 1929. Serial No. 385,179

2 Claims.

This invention relates to inclosed motor pump units which may be used for a variety of purposes and more particularly to means for lubricating the motor and the pump.

For the sake of illustration, the invention will be described as applied to a small refrigerating machine such as commonly used for household use and in which the motor and compressor are contained within a sealed casing or casings adapted to confine the lubricant and refrigerant therein.

Figure 1 is a sectional view of a horizontal unit embodying the invention.

Figure 2 is a modification of Figure 1.

Figure 3 is an end View of Figures 1 and 2 on the line X, Y.

Figures 4 and 5 are sectional views of vertical units showing further modifications.

Only sufficient of the mechanism will be shown to illustrate the invention as it is obvious that any suitable type of system and apparatus can be used and any of the usual devices, such as evaporators, condensers, expansion valves, thermostats and the like, can be used with the motor pump units herein described to make a complete refrigerating apparatus.

The inclosed motor-compressor or pump unit may be of the type shown in Figure l where 1 denotes the rotor and 2 the field of an electric motor, the shaft 3 thereof being supported in bearings 4 and 5.

The end of shaft 3 is splined to engage shaft 6 of the compressor 7, the intake or suction side of which is connected to the passage 8 and the exhaust or pressure outlet being the pipe 9.

The pipe 9 discharges into the space 10 which, together with the space about the motor forms a sealed chamber or chambers by reason of the casings 11 and 12. A passage 13 connects the space 10 with the space about the motor so that under operating conditions the same pressure exists on both sides of the center plate 14, and for all practical purposes the interior of the motor-pump unit is a single chamber so far as pressure is concerned.

An inlet 15 is provided in the plate 14 connecting to passage 8 and an outlet 16 is provided in the motor casing. 16 usually connects to a suitable condenser and expansion valve, which in turn connects to an evaporator, the return or suction line from the evaporator connecting to the inlet 15. These parts are not shown as they play no part in the operation of the lubricating system constituting this inven- (Cl. 23020'l) tion except as herein described, and may be of any suitable form.

Suitable lubricant is placed in the casing 11 up to the level indicated at 17 and, in operation, the compressor discharging at 9 builds up a pressure in 10, 13 and the space about the motor.

The U-shaped pipe 18 has its lower end 19 in the body .of lubricant and it has been found that when starting the pressure created in the chamber 10 will drive the lubricant up pipe 18 over the bend at the top and thereby cause pipe 18 to become a siphon, which however is onl;, required to lift the lubricant from the level 17 around the bend of the pipe. This action is facilitated by restricting the passage 13 between the casings so that the pressure in the chamber 10 will initially be slightly in excess of that above the motor. However, the pressure soon equalizes upon the machine operating a few moments.

Lubricant is thus fed into the ducts 20 and 21 in the compressor and motor shafts and the lubricant level 1'7 being above these ducts, lubricant will continue to flow by gravity even after the pressure equalizes in the casings.

A very small quantity of lubricant may escape from around the motor shaft 3 and run out of the bearings into the motor casing and if so, this will find its way into the outlet 16 and circulate through the system, finally returning to the main body of lubricant in the usual manner. This system is more fully described and claimed in Patent No. 1,867,719, dated July 19, 1932. This small quantity of lubricant is no greater than that which circulates in many refrigerating systems now in use and is not objectionable. Nor does this lubricant form with the refrigerant a working mixture containing enough lubricant to seal or lubricate the pump, the quantity of lubricant being so small as to have no effect as a lubricant, nor as a dilutant to the refrigerant.

As a. further means of lubricating the bearing 4, the recess 21a is provided in plate 14 immediately below the passage 13 to catch any drops of lubricant that may come over via passage 13, and this recess or lip is connected to bearing 4 by pipe 2112 which communicates via duct 210 with the bearing 4.

In Figure 2, is shown a modification wherein the passage 22 is provided leading into the suction passage 8. When in operation, suction via 8 and 22 will draw lubricant through pipe 18 and duct 20 into the compressor shaft 6 where cross-holes drilled into the duct 20 distribute lubricant to the compressor rotor and its bearings, sealing and lubricating the same.

Also, when this modification is used it is found that when the machine stops a quantity of lubricant passes via duct 21 to bearing 4 and the duct 23 is provided therein to conduct this surplus to sump 24 from which any small surplus overflows into 16 as previously described. But upon starting the unit the suction in passage 22 and pressure in the motor casing causes the lubricant in 24 to pass upwards in 23 and return via duct 21 in the motor shaft 3 to duct 22 and to suction in 8, thereby returning this surplus lubricant to the main body in casing 11, as this lubricant will pass through the pump and be ejected into space 10.

It will be observed that at no time is the motor casing under vacuum as is often the case heretofore, and that the pressures are substantially the same on both sides of plate 14.

To prevent lubricant passing from 10 into the motor casing 12, should the machine be tipped over, the ball 25 is arranged so it will roll against the end of duct 13 and prevent the lubricant in 10 entering therein.

In Figure 4 the motor and compressor are in what is practically a single casing as the interior space 26 is common to both with no difference in pressure at any time. The pressure in 26 causes lubricant to flow via pipe 2'1 to the upper bearing 28 of the motor shaft and down through the duct in this shaft to duct 22 which connects to the suction side of the pump. Lubricant also passes through the opening 29 to the compressor shaft and into the compressor as described in connection with the preceding figures and also to duct 22. There are therefore, twodistinct lubricating paths, one through the motor bearings and one through the pump parts, both taking lubricant from the main body 30, and after circulating the same, returning it to 30.

Any lubricant that escapes from the motor bearings descends by gravity to the main body 30 of lubricant.

The outlet 16 for the refrigerant being high above the lubricant level, no lubricant will circulate in the refrigeration cycle except a small quantity accidentally carried over by the refrigerant. The compressed gas leaves the pump via pipe 9 the upper end of which discharges above the lubricant level, the motor and pump casing being hot, this gas distils from any oil in the motor chamber, and gas free from oil passes out at 16 to the condenser, where it is liquefied in the usual manner.

In Figure 5 the arrangement and operation are the same as in Figure except the opening 29 in the pump bearing is omitted and all the lubricant is carried via pipe 27, first to the upper bearing 28 of the motor and then through the ducts in the motor and pump shafts to the compressor and bottom bearing 31 and via duct 22a to the suction side 8 of the compressor, from which it is ejected at 9 and returns to the main body of lubricant.

The electric motor is provided with suitable circuit terminals, one of which is shown at 32, these being mounted in gas tight relation to the casing surrounding the motor, it being understood that this casing is secured by means of bolts or in any other suitable manner to the center plate or wall, so that the interior of the machine is sealed and adapted to withstand such pressures as arise during the operation thereof.

The casing surrounding the motor may also be provided with suitable air-cooling ribs or fins 33 and while the pump casing 11 is shown in the drawings as a stamped steel casing, it is obvious that this also may be provided with similar heat radiating fins.

While this invention has been shown and described as applied to a refrigerating machine, it is not necessarily limited to this use as these motor pump units have many other uses coming within the scope of the appended claims.

I claim:

1. In an inclosed motor-pump unit, the combination with a horizontal plate of a pump mounted thereon and supported thereby, a shaft for the pump, a bearing in said plate for the shaft, an upper end plate for the pump forming a bearing for said shaft, a motor shaft having a bearing in said upper end plate and adapted to engage the pump shaft, an inlet for the pump, a passage in the base plate communicating with said inlet and said bearing, a body of lubricant about the pump, a discharge outlet from the pump above said body of lubricant, a duct having its lower end immersed in said lubricant and its upper end in communication with said motor shaft, and a casing surrounding and inclosing all of said parts secured to the base plate.

2. In an inclosed motor-pump unit, the combination with a sealed casing of a pump mounted therein and supported thereby, and discharging fluid under pressure in said casing, a motor in said casing under compressed fluid pressure drivingly connected to said compressor, a shaft for said motor, a bearing in said casing for said shaft,

an inlet for said pump, a passage connecting said bearing and said inlet, a body of lubricant under compressed fluid pressure in said casing, a discharge fluid outlet from said pump into said casing, and means forming a suction lubricant passage from said body of lubricant to said bearing.

JOHN ALFRED GRIER. 

